For most Shopify stores under roughly 10,000 contacts that mainly need welcome, cart and post-purchase emails, Omnisend is the cheaper, simpler pick. Klaviyo makes more sense once you have enough order history to use its predictive data and deeper segmentation, and someone on the team who will actually build on it. Both cover the core flows well, so price and team skill should decide it more than features.
We have not used either tool ourselves. This comparison is based on the vendors' own pages, their Shopify App Store listings, and public reviews, plus real test results from our database on the parts of the funnel that feed your email list.
Features: what each tool does well
Both tools connect to Shopify, sync orders and products, and let you build signup forms, campaigns and automated flows. Both list a 4.7-star rating on the Shopify App Store: Omnisend from about 3,200 reviews and Klaviyo from about 3,426 reviews. So the gap is in depth and pricing, not basic quality.
Where Klaviyo is stronger
- Predictive data. Klaviyo shows predicted lifetime value, churn risk and expected next order date per customer. These only switch on once you have at least 500 customers with orders, 180 days of order history, recent orders, and some customers with 3 or more orders.
- Flow tools. Klaviyo's flow builder supports conditional splits, A/B tests on send times, content and offers, and can draft a flow from a typed description.
- Ecosystem. Most Shopify agencies and freelancers know Klaviyo, so hiring help is easier.
Where Omnisend is stronger
- Simplicity. Fewer settings and a shorter setup path for a small team.
- Channels in one plan. Omnisend combines email, SMS and web push in a single automation builder, and its paid plans include unlimited web push.
- Price at scale. Covered in the next section.
Your forms matter more than either tool
Whichever tool you pick, the signup form is where the list comes from. Our data shows how much it matters: when Dave Diederen removed a store's email popup, the test lost, at -20.51% revenue per visitor. Taking the popup away did not make shoppers buy more. It cut off the list that the store's emails depended on.
So before comparing flow builders, check how each tool's forms fit your store. See our notes on popup tests and the Shopify popup apps roundup if you want forms outside your email tool.
Zero-party data from quizzes also feeds segmentation in both tools. Kasper Dolk's product finder with emotional steps produced +€89,567 in revenue lift at 100% confidence, and those quiz answers are exactly the kind of data you can pass into either platform for segments.
Pricing: Omnisend vs Klaviyo costs
Both bill by list size, but they count differently. Omnisend charges by contacts. Klaviyo charges by "active profiles", the people you can reach; it says unsubscribed and suppressed contacts do not count.
| Plan detail (as of November 2026) | Omnisend | Klaviyo |
|---|---|---|
| Free plan | 250 contacts, 500 emails/month (pricing) | 250 active profiles, 500 emails/month, $5 of mobile messages/month (pricing) |
| Entry paid plan | Standard from $16/month for 500 contacts, up to 6,000 emails/month | Email from $20/month for 251-500 active profiles (Shopify listing) |
| Higher plan | Pro from $59/month for 2,500 contacts, unlimited emails | Prices set in a plan builder by profile count |
| Discount | 30% off when you pay 3 months upfront | None listed |
| SMS | Pro plan, from $0.007 per message (Shopify listing) | Spend commitment that burns down as you send; rates vary by country (Klaviyo) |
The gap grows with your list. EmailToolTester's comparison, updated August 2026, lists Omnisend at $282/month for 25,000 contacts, while Klaviyo's pricing at 25,000 contacts starts from $400/month. It also lists Klaviyo at $150/month for 10,000 profiles on email only. Check both vendors' pricing pages for your exact list size, since these numbers change.
Billing downsides to watch
Public reviews point to one risk for each tool. A Klaviyo reviewer on the Shopify App Store reported being billed over $900 after bot signups inflated their active profile count, and found downgrading harder than upgrading. An Omnisend reviewer on its listing noted that list cleaning costs extra. On either tool, add bot protection to your forms and prune your list.
Automations: cart, welcome and post-purchase flows
Both tools ship prebuilt flows for welcome series, abandoned cart, browse or product abandonment, post-purchase and win-back. For a typical Shopify store, these few flows bring in most automated revenue, and either tool handles them. Our cart abandonment email guide covers what to put in them, and the cart abandonment software roundup lists other options.
Where Klaviyo pulls ahead is branching. If you want a cart flow that splits by predicted lifetime value, past order count or churn risk, Klaviyo has more of that data built in. If your flows are "send three emails, stop when they buy", Omnisend does the job for less.
What to test inside your flows
Our tests come from on-site changes, not emails, but they show what offers and framing can move revenue, and that results vary by store:
- Ruben's one-click 10% extra discount banner above add to cart lifted revenue per visitor by 28%. A similar one-click code in a cart email is easy to set up in both tools.
- Dave Diederen saw +11.12% conversion rate after naming the sale in the discount badge ("Summer Sale - Save 50%"). Matching the sale name in your campaign emails keeps the message consistent.
- Countdown timers are mixed. Ruben's timer test across several brands found about +10% conversion on a low-priced brand, flat on a high-priced one, and -9% on another. Kasper Dolk's store gained 25.61% conversion rate by removing a checkout countdown timer. Test timers in emails before rolling them out.
- Dave Diederen's subscribe-and-save checkbox on top repurchase products produced $346K in monthly recurring revenue in 30 days. Replenishment flows in either tool can push one-time buyers toward that offer.
@DaveDiederen@DaveDiederen
@kasper_dolk
@Rubendgrf@DaveDiederen@RubendgrfPost-purchase is the other flow worth extra care. Dave Diederen's 1-click complementary post-purchase upsell reached a 16.64% upsell conversion rate. That runs on the thank-you page through a post-purchase upsell app, not in Omnisend or Klaviyo, but your follow-up emails can repeat the same complementary product for buyers who skipped it.
Browse more results in the full test database.
Verdict: which should your Shopify store use?
Pick Omnisend if your list is small to mid-sized, you want email, SMS and push in one simple plan, and nobody on your team will spend hours building segments. It is also the better fit if cost per contact matters as your list grows.
Omnisend is not for brands that want predictive customer data or that plan to hire an email agency, since far more agencies work in Klaviyo.
Pick Klaviyo if you have enough order history to qualify for its predictive data, plan to segment by customer value, or already work with an agency that uses it.
Klaviyo is not for new stores on a tight budget that will only run a handful of basic flows. You would pay more for depth you will not use, and you need to watch the active profile count.
A quick way to decide
- Count your contacts today and estimate them in 12 months, then price both tools at that size on their pricing pages.
- Check whether you meet Klaviyo's predictive data requirements. If not, that advantage does not apply to you yet.
- Ask who will build and maintain the flows. A solo owner usually gets more done in the simpler tool.
- Set up the same welcome and cart flows on the free plan of each and see which builder you finish faster.
Both have free plans for 250 contacts, so you can try the form and flow builders before paying.